Some remarks about the flux periodicity in SQUIDS

Journal Article · Thu Nov 01 04:00:00 EST 1984 · J. Low Temp. Phys.; (United States)

DOI:https://doi.org/10.1007/BF00681197· OSTI ID:6220472

Odehnal, M; Penttinen, A

A topolotical approach is used to show that the flux periodicity of any practical single-junction rf SQUID or double-junction dc SQUID device is one flux quantum (Phi/sub 0/). The flux periodicity is independent of the number of superconducting loops and circuit inductances. The topological point of view explains how multihole configurations can be derived from a toroidal one. Weak links are considered as topological switches that allow magnetic flux lines to pass from one homotopic class of loops to another. In addition to rf SQUIDs in the hysteretic or nonhysteretic regime, we also consider resistive and dc SQUIDs. Some special caes are also introduced where the flux periodicity is not Phi/sub 0/, due to special nonlinear behavior of the weak link, due to coupling to a resonant circuit, or because of a great number of weak links in the superconducting circuit. The flux periodicity of a SQUID is a property of the weak link itself, and not of the inductances connected to it. Only the number of weak links and their mutual connection in series or parallel can change the fundamental flux periodicity of the device.

• Research Organization: Institute of Physics, Czechoslovak Academy of Sciences, Rez, Czechoslovakia
• OSTI ID: 6220472
• Journal Information: J. Low Temp. Phys.; (United States), Journal Name: J. Low Temp. Phys.; (United States) Vol. 57:3; ISSN JLTPA
• Country of Publication: United States
• Language: English

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71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ELECTRONIC EQUIPMENT
EQUIPMENT
FLUXMETERS
HYSTERESIS
JOSEPHSON EFFECT
JUNCTIONS
MAGNETIC FLUX
MATHEMATICS
MEASURING INSTRUMENTS
MICROWAVE EQUIPMENT
NONLINEAR PROBLEMS
SQUID DEVICES
SUPERCONDUCTING DEVICES
SUPERCONDUCTING JUNCTIONS
TOPOLOGY
VARIATIONS